In this Wonders of the World title, Mann (The Brooklyn Bridge) sets the story of the Great Wall into a thorough yet concisely wrought framework of Chinese history and culture. Noting that the differences between the traditions of the Chinese and those of the nomadic Mongols led to centuries of conflict, Mann describes how rulers from various dynasties--beginning with China's very first emperor, Qin Shi Huangdi, who died in 210 B.C.--attempted to build walls to protect their people from the bellicose nomads. When the Mongols became even more powerful and feared in the mid-15th century, the Ming court began the colossal task of building the Great Wall, a laborious process that Witschonke illustrates in two full-page, informatively captioned pictures. The artist also offers some enticing panoramas of Chinese landscapes and several dynamic action scenarios: on horseback, Genghis Khan and his warriors charge at the reader; and a four-page foldout shows the Mongols attacking one of the Great Wall's forts. Reproductions of Chinese art cap this accessible view of a momentous era. Ages 8-up. (Dec.)